KR101295144B1 - Back light structure and liquid crystal display device thereby - Google Patents

Abstract

The present invention relates to a liquid crystal display device for improving a problem such as thermal efficiency by providing a separate reflector in consideration of wire bonding between metal PCBs; A first reflecting plate attached to the lower cover and reflecting light; At least two metal PCBs forming at least one array on the lower cover and including light emitting devices on the array; Bonding wires to facilitate electrical connection between the metal PCBs; A second reflecting plate attached to the metal PCB and forming an intaglio at a bonding wire contact portion; An optical sheet provided on the front surface of the second reflecting plate; Characterized in that it comprises a liquid crystal panel which is fastened at a predetermined interval spaced to the front of the optical sheet.

LED backlight, metal PCB, reflector

Description

BACK LIGHT STRUCTURE AND LIQUID CRYSTAL DISPLAY DEVICE THEREBY}

1 is a cross-sectional view of a direct type liquid crystal display device having a conventional LED backlight.

FIG. 2 is a plan view showing a metal PCB arranged on the bottom cover of FIG. 1 and formed of an LED array;

3 is a cross-sectional view of a direct type liquid crystal display device having an LED backlight of the present invention.

4 is a plan view of a metal PCB forming at least two arrays configured on the bottom cover of FIG.

FIG. 5 is a view showing the R, G, B LEDs of FIG. 4 forming two arrays in a cluster on a metal PCB.

FIG. 6 is a rear view of a second reflector plate attached to a portion where at least two metal PCBs of FIG. 5 are bonded to each other through a bonding wire;

DESCRIPTION OF REFERENCE NUMERALS

234: metal PCB 236: R, G, B cluster

236a: red LED 236b: green LED

236C: blue LED

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight structure and a liquid crystal display device having the same, and more particularly, a plurality of detachable metal PCBs (Metal Printed Circuit Boards) and metals in which light emitting elements are formed in at least one array unit. The present invention relates to a backlight structure for bonding wires for electrical contact between PCBs and, in such a case, to increase thermal efficiency by applying a separate reflector on a metal PCB and a liquid crystal display device having the same.

BACKGROUND ART A direct type back-light used in a liquid crystal display of a large-sized model generally reflects light from a cold cathode fluorescent lamp to a liquid crystal panel on the front side from a reflector. In addition, a milky white scattering plate is additionally disposed in the light reflection path, so that light having a locally uniform illuminance is illuminated on the liquid crystal display. However, such a method has a problem of bringing a liquid crystal display to a large and complicated model due to problems such as the backlight thickness of the display.

In recent years, as a surface light source device, a backlight is thinned by using an LED (Light Emitting Diode) having characteristics of fast response speed, low power consumption and semi-permanent lifetime as a bipolar device that emits light only when a current passes therethrough At the same time, the brightness is improved. Above all, it is possible to reproduce images of natural color and high quality compared with conventional cold cathode tubes, and to solve the afterimage problem of moving images and recognize that it is an environmentally friendly product that does not use mercury. It is no longer a key component.

Hereinafter, a liquid crystal display device having a conventional direct-type LED backlight device will be described with reference to the drawings. As shown in FIG. 1, the liquid crystal display device has a main support 50 made of synthetic resin or SUS STEEL having a substantially rectangular frame shape as a reference, and a backlight device (not shown) (Unrepresented), and the liquid crystal panel 10 is stacked and fastened in the upper part. An upper cover 60 capable of fixing both covers the front edge of the liquid crystal panel 10 and is assembled and fastened to the main support 50 and the lower cover 30.

First, in the case of a direct-type LED backlight for providing light to the liquid crystal panel, an LED array 36 formed of at least one line of LEDs mounted on the lower cover 40 and emitting light, A plurality of PCBs (Printed Circuit Boards) 34 provided on the front surface of the PCB 34 and lighting the LED arrays 36 while being driven up and down; A diffusion plate 42 provided on the LED array 36 to reduce nonuniformity of light generated from the LED array 36 and a protective sheet 42 for protecting the prism sheet 44 and increasing the viewing angle, 46).

As shown in the drawing, a reflector 32 formed on a lower front surface of a region where the PCB 34 is driven, and an LED array 36 formed of at least one line, And a reflector 38 formed on a printed circuit board 34 of a printed circuit board 34. The reflector 38 formed on one printed circuit board 34 forms a hole in the LED area, It is a little different. The reflection plates 32 and 38 are usually formed by coating a white polyester film with a reflective film such as a metal (Ag, Al) or the like. In some cases, a silicon oxide (SiO ₂ ) Scattering particles are mixed and cured.

When the backlight device is primarily completed as described above, the main support 50 made of a synthetic resin or sus steel mold having a substantially rectangular frame shape is fastened, and then the liquid crystal panel 10 is loaded on the upper side. do. Of course, the liquid crystal panel 10 here is composed of a thin film transistor array substrate and a color filter substrate bonded together, and liquid crystal injected therebetween.

FIG. 2 is a plan view illustrating a plurality of PCBs arranged and fixed on the lower cover 30 as shown in FIG. 1. Conventionally, about 8 PCB arrays are used based on 32-inch LCD display, but due to the high temperature heat generation problem related to the LEDs fixed on the PCB, the PCB is separated from the back. There is a trend to use metal PCB formed by coating the metal material. Although not shown separately in the drawings, such a metal PCB is fastened on a lower cover 30 by fixing on a metal bar such as aluminum.

However, for such a large LCD display it is natural to use a metal PCB that meets the specifications. In other words, the metal PCB used for the 32-inch LCD display and the metal PCB used for the 40-inch LCD display have different specifications. Therefore, it is not possible to actively cope with the demand of LED backlight, which starts to increase rapidly in recent years, which may significantly reduce the production efficiency, as well as cost problems due to overproduction of the product.

Therefore, an object of the present invention may be a consumer of a metal PCB, that is, a manufacturer of an LCD display, to proactively cope with their demands to allow extended connection between metal PCBs, and in some cases may also be separated between metal PCBs A backlight structure and a liquid crystal display device having the same are provided.

In addition, it is an object of the present invention to provide a backlight structure that can improve the thermal efficiency of the reflector by providing a separate reflector in consideration of wire bonding for the connection between metal PCB and a liquid crystal display device having the same.

And the above object can be achieved through the present invention. That is, the liquid crystal display according to the present invention includes a lower cover; A first reflecting plate attached to the lower cover and reflecting light; At least two metal PCBs forming at least one array on the lower cover and including light emitting devices on the array; Bonding wires to facilitate electrical connection between the metal PCBs; A second reflecting plate attached to the metal PCB and forming an intaglio at a bonding wire contact portion; An optical sheet provided on the front surface of the second reflecting plate; Characterized in that it comprises a liquid crystal panel which is fastened at a predetermined interval spaced to the front of the optical sheet.

In addition, the backlight structure of the liquid crystal display according to the present invention includes a lower cover; A first reflecting plate attached to the lower cover and reflecting light; At least two metal PCBs forming at least one array on the lower cover and including light emitting devices on the array; Bonding wires to facilitate electrical connection between the metal PCBs; A second reflecting plate attached to the metal PCB and forming an intaglio at a bonding wire contact portion; And an optical sheet provided on the front surface of the second reflecting plate.

Then, with reference to the drawings with respect to the above configuration will be described in more detail. 3 is a cross-sectional view of a liquid crystal display device according to the present invention. According to the fastening order, as shown in the drawing, the direct type LED backlight device for providing light to the liquid crystal panel is first fastened on the lower cover 130. As a first priority, the reflective plate covering the front surface on the lower cover 130 ( 132). This is called the first reflecting plate 132 in the present invention.

In addition, above the first reflecting plate 132, the metal PCBs 134 fastened to an array of a plurality of LEDs are disposed to correspond to each other. In the drawing, the two metal PCBs 134 fastened to an array of a plurality of LEDs. ) Is shown electrically connected. As used herein, the term “electrical connection” refers to a process of bonding the wire 140 between the metal PCBs 134, which is formed on at least two metal PCBs 134, for example, red (R), green ( G), the blue LEDs are connected to each other to apply a voltage through a driver (not shown).

Another reflector plate 138 is now attached to at least two metal PCBs 134 interconnected by wire 140 bonding in forming one array. Unlike the first reflecting plate 132, since it is attached to each metal PCB 134 constituting the array, it is inevitably different in size.
Therefore, in the present invention, such a reflector attached to the array-specific metal PCB 134 is called a second reflector 138. Of course, in the shape of the second reflecting plate 138 at first glance, it is needless to say that the light emitting device, that is, to form and manufacture a hole for each LED part, will be mentioned. 138) is forming an intaglio at the bottom. This is because the second reflecting plate 138 is in close contact with the metal PCB 134 in view of the effect of the other, because it can prevent the lifting of the second reflecting plate 138, thereby increasing the efficiency of light It is also.

The diffuser plate 142 that mitigates the non-uniformity of the light emitted from the LED 136 and the diffuser plate 142 penetrate the upper portion of the at least two metal PCBs 134 on which the LEDs forming the at least one array are formed. The prism sheet 144 for increasing the brightness of light and the protective sheet 146 for protecting the prism sheet 144 and increasing the viewing angle are loaded.

When the configuration of the primary backlight is completed as described above, the main support 150 is fastened to maintain the balance of the overall force of the liquid crystal display. A certain pattern is formed for the liquid crystal panel 110 on the upper side as a mold of a synthetic resin or SUS STEEL having a substantially rectangular frame shape and surrounds the outer periphery of the lower cover 130 as shown in the figure Respectively.

On the other hand, the liquid crystal panel 110 for loading the light from the lower backlight on the main support 150 to implement data information from the outside is loaded. Of course, the liquid crystal panel 110 includes a liquid crystal injected between the thin film transistor array substrate and the color filter substrate.

And the upper cover 160 that can fix all of these cover the four edges of the liquid crystal panel 110 and is assembled to the main support 150 and the lower cover 130.

FIG. 4 is a plan view of a metal PCB forming at least one array of lower components 130 of the above components. In particular, we will look more closely at the mutual coupling of at least one array and at least two metal PCBs 134. As shown in the figure, an LED array 136 is formed on the metal PCB 134 by forming at least one line of LEDs emitting light. In other words, one array is composed of at least two metal PCBs 134, which, to one embodiment, is a minimum condition. Substantially based on a 32-inch LCD display, the metal PCB 134 may be configured with at least five or more. However, if it is 40 inches, it could be more. In addition, although FIG. 4 forms one array on at least one metal PCB 134 and LEDs 136 are formed, the present invention extends this to one or more LED arrays 136 on one metal PCB 134. Presuppose that a) can be formed.

In addition, although the mutual coupling of the at least two metal PCB 134 is mentioned above, the electrical connection is made through the bonding wire 140. Here, the metal PCB 134 is formed by coating a separate metal material on the back surface due to a high temperature heat generation problem associated with the red (R), green (G), and blue (B) LEDs. Is preferably formed in the same direction as the light emitting portion of the LED 136. Since two lines of cathode and anode are used for each of the R, G, and B LEDs, a total of six wires are formed.

As described above, at least two metal PCBs 134 coupled to each other through the wire 140 are fastened on the lower cover 130 by being fixed on a metal bar such as aluminum, although not separately shown in FIG. 3.

FIG. 5 shows the LEDs 236a to 236c of FIG. 4 configured as one cluster on the metal PCB 234 to form two arrays. In this regard, the contents of at least one cluster array formed on one metal PCB 234 and at least two metal PCBs 234 fastened on the lower cover have been described in detail with reference to FIG. 4. Here, the cluster 236 surrounding the R, G, and B LEDs 236a to 236c is formed of a material such as silicon.

FIG. 6 is a rear view of the second reflecting plate attached to a portion where at least two metal PCBs 134 of FIG. 5 are bonded to each other through a bonding wire. As shown in the drawing, a hole 336 is formed in an area corresponding to the cluster, and a height of the bonding wire (not shown in FIG. 5, 240) in an area corresponding to the bonding wire (not shown in FIG. 5). The indentation 340 is formed to form a step, and the number of the indentations 340 is substantially excluded from the contact with the LED driver, assuming that approximately N metal PCBs are substantially mutually coupled to each other based on one array. If it is, it is preferable to be formed by (N-1) pieces.

In addition, the second reflector 338 may be formed of, for example, a film of white polyester as its base layer, and a coated film such as metal (Ag, Al) may be formed as a reflective layer thereon. The intaglio 340 portion of the second reflector 338 according to the present invention can be seen to be formed under the base layer.

As described above, the liquid crystal display device according to the present invention can enable the extension or separation of the metal PCB in order to flexibly cope with the demand of the metal PCB used in the LED backlight of various large model LCD, as well as the metal PCB By providing a separate reflector in consideration of inter-wire bonding, problems such as thermal efficiency can be improved.

Claims (10)

Lower cover; A first reflecting plate attached to the lower cover and reflecting light; At least two metal PCBs disposed corresponding to each other on the first reflecting plate on the lower cover, and each of which has an array of a plurality of light emitting elements coupled thereto; Bonding wires electrically connecting the metal PCBs disposed corresponding to each other; A second reflecting plate attached to the metal PCBs corresponding to each other, the second reflecting plate being formed to be in close contact with the bonding wires and having an intaglio forming a step by a height of the bonding wires in close contact with the bonding wires; An optical sheet provided on the front surface of the second reflecting plate; A liquid crystal panel fastened at a predetermined interval to the front of the optical sheet; And the intaglio is formed on a bottom surface of the second reflecting plate in contact with the bonding wire. The liquid crystal display of claim 1, wherein the second reflector further forms holes in portions corresponding to light emitting elements on the metal PCB. The liquid crystal display device according to claim 1, wherein the light emitting element is a red (R), green (G), or blue (B) LED. The liquid crystal display of claim 1, wherein the light emitting element is a cluster including red (R), green (G), and blue (B) LEDs. The optical sheet of claim 1, further comprising: a diffusion plate that mitigates the nonuniformity of light emitted from the light emitting elements; A prism sheet for increasing the luminance of light passing through the diffusion plate; And a protective sheet which protects the prism sheet and increases the viewing angle. Lower cover; A first reflecting plate attached to the lower cover and reflecting light; At least two metal PCBs disposed corresponding to each other on the first reflecting plate on the lower cover, and each of which has an array of a plurality of light emitting elements coupled thereto; Bonding wires electrically connecting the metal PCBs disposed corresponding to each other; A second reflecting plate attached to the metal PCBs corresponding to each other, the second reflecting plate being in close contact with the bonding wires and having an intaglio which forms a step as high as the height of the bonding wires and closely disposed on the metal PCBs; An optical sheet provided on the front surface of the second reflecting plate; The recess is formed on the bottom surface of the second reflecting plate in contact with the bonding wires. The backlight structure of claim 6, wherein the second reflector further forms holes in portions corresponding to the light emitting elements on the metal PCB. The backlight structure of a liquid crystal display device according to claim 6, wherein the light emitting element is a red (R), green (G), or blue (B) LED. 7. The backlight structure of claim 6, wherein the light emitting element is one cluster including red (R), green (G), and blue (B) LEDs. The optical sheet of claim 6, further comprising: a diffusion plate that mitigates the nonuniformity of light emitted from the light emitting elements; A prism sheet for increasing the luminance of light passing through the diffusion plate; And a protective sheet which protects the prism sheet and increases the viewing angle.

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